I never noticed there was a L4D2 update but recently the game has become a laggy piece of ♥♥♥♥. Nothing on my PC has changed at all for a very long time and now, for some reason, it stutters like crazy no matter what. I'm pretty sure its no problem on my end since the game always ran flawlessly on maxed out settings etc.

There are only a few other discussions about this lag/stuttering so I don't really know what could be causing this other than an update apparently. Any ideas on whats causing this? Other than suggestions to lower my graphical settings even though I shouldn't have to since nothing is different about MY PC.

I tried turning off V sync and the multicore rendering etc. but everything is still the same. I also disabled my antivirus temporarily and nothing changed. Maybe it could be my graphics driver or something, I don't know.

No. I've been playing on Local servers. Whether its online or Single Player it just stutters every 5 ish seconds I guess. Also it's only with Left 4 Dead. Every one of my other games runs perfect maxed out etc.

cl_forcepreload 1 //Whether we should force preloading model and texture information to video memory at the beginning of a level. Makes level loads longer, but can reduce stuttering caused by loading information on the fly.

The autoexec.cfg you will have to make unless you already ahve one, goto C:\Program Files (x86)\Steam\SteamApps\common\left 4 dead 2\left4dead2\cfg (win x64Bit) or C:\Program Files\Steam\SteamApps\common\left 4 dead 2\left4dead2\cfg (win x32Bit) and right click and slect new text file inside of this copy and paste the preload cmd then save it, make sure you name it / save it as "autoexec.cfg" not autoexec.cfg/txt"

Then we can't help. Only thing i'd recommend is to use gamebooster 3 or some stuff that reduces your memory usage. It's been several threads with people having the same problem. I have probably the most weak machine here and it's not having any of this ♥♥♥♥tering. Or else you are using HD textures? Hell with it. Know unstalling won't change anything so try and figure by tweaking your system and game.

By the way is that "♥♥♥♥tering" so bad? A little lag spike can't be this terrible. I've experienced FPS drops in the past years, but those are gone now. It was related to steam taking 50% of ram without any reasons. If you can please tell me if it actually do the same.

I never had to use any of those boosters normally even with very demanding games but I have tried and it still stutters. I mostly just have weapon mods and maybe a few item retextures and maybe some other stuff I'm forgetting but they look like the same resolution as the vanilla stuff. Even then if I had HD textures, I haven't changed anything for a long time so why would it stutter now?

After checking performance in WTM everything looks normal. The app can use more than 2 GB, I checked. It stutters at a constant interval of 5 seconds (ish), if that means anything. The lag spike isn't 'terrible', it's just generally annoying and throws my aim off most of the time. I don't think its my memory being used up by something else since I always close or disable unnecessary applications etc. before I play something.

Uh, I guess so. There's only a few optional updates. Everything else like all my drivers are the latest or Beta. I'm using the 320 Nvidia Beta graphical driver, and there was a few comments about some minor problems with it on a few games so I guess I'll try changing it back. If it was the drivers all along I'll feel so stupid.

Portal 2 was stuttering as well but I turned off Multicore rendering or whatever it is, vertical sync and changed my computers power plan to High Performance. It seems to be fine but the sound seems to 'crackle' every 10 seconds or when loading a new area or something. I tried the same thing with L4D2 and its still the same. CS:GO is fine, so it isn't all Source/Valve games.